"""Migration routines for SMB and NFS shares."""
from __future__ import annotations

import json
from typing import Any

from .colors import log, _bold, _bold_cyan, _bold_green, _bold_red, _cyan, _yellow
from .client import TrueNASClient
from .summary import Summary


# ─────────────────────────────────────────────────────────────────────────────
# Payload builders
# ─────────────────────────────────────────────────────────────────────────────

# Read-only / server-generated fields that must NOT be sent on create/update
_SMB_SHARE_READONLY = frozenset({"id", "locked"})

# CORE SMB share fields that do not exist in the SCALE API
_SMB_SHARE_CORE_EXTRAS = frozenset({
    "vuid",   # server-generated Time Machine UUID; SCALE sets this automatically
})

# CORE NFS share fields that do not exist in the SCALE API
_NFS_SHARE_CORE_EXTRAS = frozenset({
    "paths",    # CORE uses a list; SCALE uses a single "path" string (converted below)
    "alldirs",  # removed in SCALE
    "quiet",    # removed in SCALE
})


def _smb_share_payload(share: dict) -> dict:
    exclude = _SMB_SHARE_READONLY | _SMB_SHARE_CORE_EXTRAS
    return {k: v for k, v in share.items() if k not in exclude}


def _nfs_share_payload(share: dict) -> dict:
    payload = {k: v for k, v in share.items()
               if k not in {"id", "locked"} | _NFS_SHARE_CORE_EXTRAS}
    # CORE stores export paths as a list under "paths"; SCALE expects a single "path" string.
    if "path" not in payload and share.get("paths"):
        payload["path"] = share["paths"][0]
    return payload


# ─────────────────────────────────────────────────────────────────────────────
# Migration routines
# ─────────────────────────────────────────────────────────────────────────────

async def migrate_smb_shares(
    client: TrueNASClient,
    shares: list[dict],
    dry_run: bool,
    summary: Summary,
) -> None:
    summary.smb_found = len(shares)
    if not shares:
        log.info("No SMB shares found in archive.")
        return

    log.info("Querying existing SMB shares on destination …")
    try:
        existing = await client.call("sharing.smb.query") or []
    except RuntimeError as exc:
        msg = f"Could not query SMB shares: {exc}"
        log.error(msg)
        summary.errors.append(msg)
        return

    existing_names = {s.get("name", "").lower() for s in existing}
    log.info("  Destination has %d existing SMB share(s).", len(existing_names))

    for share in shares:
        name = share.get("name", "<unnamed>")
        log.info("%s SMB share %s", _bold("──"), _bold_cyan(repr(name)))

        if name.lower() in existing_names:
            log.info("   %s – already exists on destination.", _yellow("SKIP"))
            summary.smb_skipped += 1
            continue

        payload = _smb_share_payload(share)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create %s → %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(name)), payload.get("path"))
            summary.smb_created += 1
            if payload.get("path"):
                summary.paths_to_create.append(payload["path"])
            continue

        try:
            r = await client.call("sharing.smb.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            summary.smb_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.smb_failed += 1
            summary.errors.append(f"SMB share {name!r}: {exc}")


async def migrate_nfs_shares(
    client: TrueNASClient,
    shares: list[dict],
    dry_run: bool,
    summary: Summary,
) -> None:
    summary.nfs_found = len(shares)
    if not shares:
        log.info("No NFS shares found in archive.")
        return

    log.info("Querying existing NFS shares on destination …")
    try:
        existing = await client.call("sharing.nfs.query") or []
    except RuntimeError as exc:
        msg = f"Could not query NFS shares: {exc}"
        log.error(msg)
        summary.errors.append(msg)
        return

    existing_paths = {s.get("path", "").rstrip("/") for s in existing}
    log.info("  Destination has %d existing NFS share(s).", len(existing_paths))

    for share in shares:
        core_paths = share.get("paths") or []
        path = (share.get("path") or (core_paths[0] if core_paths else "")).rstrip("/")
        all_paths = [p.rstrip("/") for p in (core_paths if core_paths else ([path] if path else []))]
        log.info("%s NFS export %s", _bold("──"), _bold_cyan(repr(path)))

        if path in existing_paths:
            log.info("   %s – path already exported on destination.", _yellow("SKIP"))
            summary.nfs_skipped += 1
            continue

        payload = _nfs_share_payload(share)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create NFS export for %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(path)))
            summary.nfs_created += 1
            summary.paths_to_create.extend(all_paths)
            continue

        try:
            r = await client.call("sharing.nfs.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            summary.nfs_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.nfs_failed += 1
            summary.errors.append(f"NFS share {path!r}: {exc}")


# ─────────────────────────────────────────────────────────────────────────────
# iSCSI payload builders
# ─────────────────────────────────────────────────────────────────────────────

_ISCSI_EXTENT_READONLY    = frozenset({"id", "serial", "naa", "vendor", "locked"})
_ISCSI_INITIATOR_READONLY = frozenset({"id"})
_ISCSI_PORTAL_READONLY    = frozenset({"id", "tag"})
_ISCSI_TARGET_READONLY    = frozenset({"id", "rel_tgt_id", "iscsi_parameters"})


def _iscsi_extent_payload(extent: dict) -> dict:
    payload = {k: v for k, v in extent.items() if k not in _ISCSI_EXTENT_READONLY}
    if extent.get("type") == "DISK":
        payload.pop("path", None)      # derived from disk on DISK extents
        payload.pop("filesize", None)  # only meaningful for FILE extents
    else:
        payload.pop("disk", None)
    return payload


def _iscsi_initiator_payload(initiator: dict) -> dict:
    return {k: v for k, v in initiator.items() if k not in _ISCSI_INITIATOR_READONLY}


def _iscsi_portal_payload(portal: dict) -> dict:
    payload = {k: v for k, v in portal.items() if k not in _ISCSI_PORTAL_READONLY}
    # The API only accepts {"ip": "..."} in listen entries — port is a global setting
    payload["listen"] = [{"ip": l["ip"]} for l in payload.get("listen", [])]
    return payload


def _iscsi_target_payload(
    target: dict,
    portal_id_map: dict[int, int],
    initiator_id_map: dict[int, int],
) -> dict:
    payload = {k: v for k, v in target.items() if k not in _ISCSI_TARGET_READONLY}
    payload["groups"] = [
        {**g,
         "portal":    portal_id_map.get(g["portal"], g["portal"]),
         "initiator": initiator_id_map.get(g.get("initiator"), g.get("initiator"))}
        for g in target.get("groups", [])
    ]
    return payload


# ─────────────────────────────────────────────────────────────────────────────
# iSCSI migration sub-routines
# ─────────────────────────────────────────────────────────────────────────────

async def _migrate_iscsi_extents(
    client: TrueNASClient,
    extents: list[dict],
    dry_run: bool,
    summary: Summary,
    id_map: dict[int, int],
) -> None:
    log.info("Querying existing iSCSI extents on destination …")
    try:
        existing = await client.call("iscsi.extent.query") or []
    except RuntimeError as exc:
        msg = f"Could not query iSCSI extents: {exc}"
        log.error(msg); summary.errors.append(msg); return

    existing_by_name = {e["name"].lower(): e for e in existing}
    log.info("  Destination has %d existing extent(s).", len(existing_by_name))

    for ext in extents:
        name = ext.get("name", "<unnamed>")
        log.info("%s iSCSI extent %s", _bold("──"), _bold_cyan(repr(name)))

        if name.lower() in existing_by_name:
            log.info("   %s – already exists on destination.", _yellow("SKIP"))
            id_map[ext["id"]] = existing_by_name[name.lower()]["id"]
            summary.iscsi_extents_skipped += 1
            continue

        payload = _iscsi_extent_payload(ext)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create extent %s → %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(name)),
                     ext.get("disk") or ext.get("path"))
            summary.iscsi_extents_created += 1
            if ext.get("type") == "DISK" and ext.get("disk"):
                summary.zvols_to_check.append(ext["disk"].removeprefix("zvol/"))
            continue

        try:
            r = await client.call("iscsi.extent.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            id_map[ext["id"]] = r["id"]
            summary.iscsi_extents_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.iscsi_extents_failed += 1
            summary.errors.append(f"iSCSI extent {name!r}: {exc}")


async def _migrate_iscsi_initiators(
    client: TrueNASClient,
    initiators: list[dict],
    dry_run: bool,
    summary: Summary,
    id_map: dict[int, int],
) -> None:
    log.info("Querying existing iSCSI initiator groups on destination …")
    try:
        existing = await client.call("iscsi.initiator.query") or []
    except RuntimeError as exc:
        msg = f"Could not query iSCSI initiators: {exc}"
        log.error(msg); summary.errors.append(msg); return

    existing_by_comment = {e["comment"].lower(): e for e in existing if e.get("comment")}
    log.info("  Destination has %d existing initiator group(s).", len(existing))

    for init in initiators:
        comment = init.get("comment", "")
        log.info("%s iSCSI initiator group %s", _bold("──"), _bold_cyan(repr(comment)))

        if comment and comment.lower() in existing_by_comment:
            log.info("   %s – comment already exists on destination.", _yellow("SKIP"))
            id_map[init["id"]] = existing_by_comment[comment.lower()]["id"]
            summary.iscsi_initiators_skipped += 1
            continue

        payload = _iscsi_initiator_payload(init)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create initiator group %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(comment)))
            summary.iscsi_initiators_created += 1
            continue

        try:
            r = await client.call("iscsi.initiator.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            id_map[init["id"]] = r["id"]
            summary.iscsi_initiators_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.iscsi_initiators_failed += 1
            summary.errors.append(f"iSCSI initiator {comment!r}: {exc}")


async def _migrate_iscsi_portals(
    client: TrueNASClient,
    portals: list[dict],
    dry_run: bool,
    summary: Summary,
    id_map: dict[int, int],
) -> None:
    log.info("Querying existing iSCSI portals on destination …")
    try:
        existing = await client.call("iscsi.portal.query") or []
    except RuntimeError as exc:
        msg = f"Could not query iSCSI portals: {exc}"
        log.error(msg); summary.errors.append(msg); return

    def _ip_set(p: dict) -> frozenset:
        return frozenset(l["ip"] for l in p.get("listen", []))

    existing_ip_sets = [(_ip_set(p), p["id"]) for p in existing]
    log.info("  Destination has %d existing portal(s).", len(existing))

    for portal in portals:
        comment = portal.get("comment", "")
        ips = ", ".join(l['ip'] for l in portal.get("listen", []))
        log.info("%s iSCSI portal %s [%s]", _bold("──"), _bold_cyan(repr(comment)), ips)

        my_ips = _ip_set(portal)
        match = next((eid for eips, eid in existing_ip_sets if eips == my_ips), None)
        if match is not None:
            log.info("   %s – IP set already exists on destination.", _yellow("SKIP"))
            id_map[portal["id"]] = match
            summary.iscsi_portals_skipped += 1
            continue

        payload = _iscsi_portal_payload(portal)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create portal %s → %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(comment)), ips)
            summary.iscsi_portals_created += 1
            continue

        try:
            r = await client.call("iscsi.portal.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            id_map[portal["id"]] = r["id"]
            summary.iscsi_portals_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.iscsi_portals_failed += 1
            summary.errors.append(f"iSCSI portal {comment!r}: {exc}")


async def _migrate_iscsi_targets(
    client: TrueNASClient,
    targets: list[dict],
    dry_run: bool,
    summary: Summary,
    id_map: dict[int, int],
    portal_id_map: dict[int, int],
    initiator_id_map: dict[int, int],
) -> None:
    log.info("Querying existing iSCSI targets on destination …")
    try:
        existing = await client.call("iscsi.target.query") or []
    except RuntimeError as exc:
        msg = f"Could not query iSCSI targets: {exc}"
        log.error(msg); summary.errors.append(msg); return

    existing_by_name = {t["name"].lower(): t for t in existing}
    log.info("  Destination has %d existing target(s).", len(existing_by_name))

    for target in targets:
        name = target.get("name", "<unnamed>")
        log.info("%s iSCSI target %s", _bold("──"), _bold_cyan(repr(name)))

        if name.lower() in existing_by_name:
            log.info("   %s – already exists on destination.", _yellow("SKIP"))
            id_map[target["id"]] = existing_by_name[name.lower()]["id"]
            summary.iscsi_targets_skipped += 1
            continue

        # Verify all referenced portals and initiators were successfully mapped
        missing = []
        for g in target.get("groups", []):
            if g.get("portal") not in portal_id_map:
                missing.append(f"portal id={g['portal']}")
            if g.get("initiator") not in initiator_id_map:
                missing.append(f"initiator id={g['initiator']}")
        if missing:
            msg = f"iSCSI target {name!r}: cannot remap {', '.join(missing)}"
            log.error("   %s: %s", _bold_red("SKIP"), msg)
            summary.iscsi_targets_failed += 1
            summary.errors.append(msg)
            continue

        payload = _iscsi_target_payload(target, portal_id_map, initiator_id_map)
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would create target %s",
                     _cyan("[DRY RUN]"), _bold_cyan(repr(name)))
            summary.iscsi_targets_created += 1
            continue

        try:
            r = await client.call("iscsi.target.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            id_map[target["id"]] = r["id"]
            summary.iscsi_targets_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.iscsi_targets_failed += 1
            summary.errors.append(f"iSCSI target {name!r}: {exc}")


async def _migrate_iscsi_targetextents(
    client: TrueNASClient,
    targetextents: list[dict],
    dry_run: bool,
    summary: Summary,
    target_id_map: dict[int, int],
    extent_id_map: dict[int, int],
) -> None:
    log.info("Querying existing iSCSI target-extent associations on destination …")
    try:
        existing = await client.call("iscsi.targetextent.query") or []
    except RuntimeError as exc:
        msg = f"Could not query iSCSI target-extents: {exc}"
        log.error(msg); summary.errors.append(msg); return

    existing_keys = {(te["target"], te["lunid"]) for te in existing}
    log.info("  Destination has %d existing association(s).", len(existing))

    for te in targetextents:
        src_tid = te["target"]
        src_eid = te["extent"]
        lunid   = te["lunid"]
        dest_tid = target_id_map.get(src_tid)
        dest_eid = extent_id_map.get(src_eid)

        if dest_tid is None or dest_eid is None:
            missing = []
            if dest_tid is None: missing.append(f"target id={src_tid}")
            if dest_eid is None: missing.append(f"extent id={src_eid}")
            msg = f"iSCSI target-extent (lun {lunid}): cannot remap {', '.join(missing)}"
            log.error("   %s", msg)
            summary.iscsi_targetextents_failed += 1
            summary.errors.append(msg)
            continue

        log.info("%s iSCSI target↔extent  target=%s  lun=%s  extent=%s",
                 _bold("──"), dest_tid, lunid, dest_eid)

        if (dest_tid, lunid) in existing_keys:
            log.info("   %s – target+LUN already assigned on destination.", _yellow("SKIP"))
            summary.iscsi_targetextents_skipped += 1
            continue

        payload = {"target": dest_tid, "lunid": lunid, "extent": dest_eid}
        log.debug("   payload: %s", json.dumps(payload))

        if dry_run:
            log.info("   %s would associate target=%s  lun=%s  extent=%s",
                     _cyan("[DRY RUN]"), dest_tid, lunid, dest_eid)
            summary.iscsi_targetextents_created += 1
            continue

        try:
            r = await client.call("iscsi.targetextent.create", [payload])
            log.info("   %s  id=%s", _bold_green("CREATED"), r.get("id"))
            summary.iscsi_targetextents_created += 1
        except RuntimeError as exc:
            log.error("   %s: %s", _bold_red("FAILED"), exc)
            summary.iscsi_targetextents_failed += 1
            summary.errors.append(
                f"iSCSI target-extent (target={dest_tid}, lun={lunid}): {exc}")


# ─────────────────────────────────────────────────────────────────────────────
# Public iSCSI entry point
# ─────────────────────────────────────────────────────────────────────────────

async def migrate_iscsi(
    client: TrueNASClient,
    iscsi: dict,
    dry_run: bool,
    summary: Summary,
) -> None:
    if not iscsi:
        log.info("No iSCSI configuration found in archive.")
        return

    portals       = iscsi.get("portals", [])
    initiators    = iscsi.get("initiators", [])
    targets       = iscsi.get("targets", [])
    extents       = iscsi.get("extents", [])
    targetextents = iscsi.get("targetextents", [])

    summary.iscsi_extents_found       = len(extents)
    summary.iscsi_initiators_found    = len(initiators)
    summary.iscsi_portals_found       = len(portals)
    summary.iscsi_targets_found       = len(targets)
    summary.iscsi_targetextents_found = len(targetextents)

    gc = iscsi.get("global_config", {})
    if gc.get("basename"):
        log.info("  Source iSCSI basename: %s  (destination keeps its own)", gc["basename"])

    if not any([portals, initiators, targets, extents, targetextents]):
        log.info("iSCSI configuration is empty – nothing to migrate.")
        return

    extent_id_map:    dict[int, int] = {}
    initiator_id_map: dict[int, int] = {}
    portal_id_map:    dict[int, int] = {}
    target_id_map:    dict[int, int] = {}

    # Dependency order: extents and initiators first (no deps), then portals,
    # then targets (need portal + initiator maps), then target-extent links.
    await _migrate_iscsi_extents(client, extents, dry_run, summary, extent_id_map)
    await _migrate_iscsi_initiators(client, initiators, dry_run, summary, initiator_id_map)
    await _migrate_iscsi_portals(client, portals, dry_run, summary, portal_id_map)
    await _migrate_iscsi_targets(
        client, targets, dry_run, summary, target_id_map, portal_id_map, initiator_id_map)
    await _migrate_iscsi_targetextents(
        client, targetextents, dry_run, summary, target_id_map, extent_id_map)