"""Lightweight schema sync for additive/structural changes.

`Base.metadata.create_all` creates NEW tables but never alters existing ones,
so this module applies the missing pieces at startup:

1. `drop_legacy()` — tables whose shape changed or whose feature was removed
   (including all legacy cache & sync tables).
2. `ensure_schema()` — additive columns and new enum values.
"""
import logging

from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncConnection

logger = logging.getLogger("pm.schema")

# Tables dropped on startup (idempotent):
# - legacy cache & sync tables completely purged
# - legacy inspection / activity template tables
LEGACY_TABLES: list[str] = [
    "material_requirements",
    "reservations",
    "milestones",
    "purchase_requests",
    "inspection_results",
    "inspections",
    "activity_template_materials",
    "activity_templates",
    "projects_cache",
    "task_refs",
    "sync_events",
    "integration_logs",
    "webhook_deliveries",
    "sync_state",
]

LEGACY_COLUMNS: list[tuple[str, str]] = [
    ("projects", "client"),
    ("projects", "code"),
    ("projects", "erp_project_id"),
    ("tasks", "planned_progress"),
    ("projects", "legacy_op_project_id"),
    ("tasks", "legacy_op_wp_id"),
    ("task_qc_definitions", "task_op_wp_id"),
    ("defects", "task_op_wp_id"),
    ("project_assignments", "op_project_id"),
    ("tasks", "equipment"),
]

ADDITIVE_COLUMNS: list[tuple[str, str, str]] = [
    # (table, column, type)
    # RBAC: users that predate roles keep their previous (manager) access
    ("pm_users", "role", "VARCHAR(32) NOT NULL DEFAULT 'project_manager'"),
    # Native PM Platform linking
    ("task_qc_definitions", "task_id", "UUID"),
    ("defects", "task_id", "UUID"),
    ("project_assignments", "project_id", "UUID"),
    ("tasks", "human_resources", "JSONB DEFAULT '[]'"),
    ("tasks", "materials", "JSONB DEFAULT '[]'"),
    ("task_qc_results", "photo_path", "VARCHAR(512)"),
]

ENUM_VALUES: list[tuple[str, str]] = [
    # (enum type, value) — e.g. the pre-execution QC stage
    ("qc_phase", "pre"),
]


async def drop_legacy(conn: AsyncConnection) -> None:
    # Migrate any existing equipment data to materials before dropping the equipment column
    try:
        check = await conn.execute(
            text("SELECT 1 FROM information_schema.columns WHERE table_name = 'tasks' AND column_name = 'equipment'")
        )
        if check.scalar():
            await conn.execute(
                text("""
                    UPDATE tasks
                    SET materials = COALESCE(materials, '[]'::jsonb) || (
                        SELECT COALESCE(jsonb_agg(
                            jsonb_build_object(
                                'name', elem->>'name',
                                'unit', COALESCE(elem->>'unit', 'دستگاه'),
                                'specifications', COALESCE(elem->'specifications', '[]'::jsonb),
                                'count', COALESCE((elem->>'count')::numeric, 1)
                            )
                        ), '[]'::jsonb)
                        FROM jsonb_array_elements(equipment) AS elem
                        WHERE elem->>'name' IS NOT NULL AND elem->>'name' != ''
                    )
                    WHERE equipment IS NOT NULL AND jsonb_array_length(equipment) > 0;
                """)
            )
            logger.info("Migrated equipment data into materials in tasks table.")
    except Exception as exc:  # noqa: BLE001
        logger.warning("equipment migration skipped: %s", exc)

    for table in LEGACY_TABLES:
        try:
            await conn.execute(text(f"DROP TABLE IF EXISTS {table} CASCADE"))
        except Exception as exc:  # noqa: BLE001 — never block startup on this
            logger.warning("legacy drop skipped %s: %s", table, exc)

    for table, column in LEGACY_COLUMNS:
        try:
            await conn.execute(text(f"ALTER TABLE IF EXISTS {table} DROP COLUMN IF EXISTS {column} CASCADE"))
        except Exception as exc:  # noqa: BLE001
            logger.warning("legacy column drop skipped %s.%s: %s", table, column, exc)


async def ensure_schema(conn: AsyncConnection) -> None:
    for enum_type, value in ENUM_VALUES:
        try:
            await conn.execute(text(f"ALTER TYPE {enum_type} ADD VALUE IF NOT EXISTS '{value}'"))
        except Exception as exc:  # noqa: BLE001
            logger.warning("enum sync skipped %s.%s: %s", enum_type, value, exc)

    for table, column, coltype in ADDITIVE_COLUMNS:
        try:
            await conn.execute(text(f"ALTER TABLE IF EXISTS {table} ADD COLUMN IF NOT EXISTS {column} {coltype}"))
        except Exception as exc:  # noqa: BLE001
            logger.warning("schema sync skipped %s.%s: %s", table, column, exc)

    try:
        await conn.execute(text("""
            CREATE TABLE IF NOT EXISTS task_progress_logs (
                id UUID PRIMARY KEY,
                task_id UUID NOT NULL REFERENCES tasks(id) ON DELETE CASCADE,
                progress_before INTEGER DEFAULT 0,
                progress_after INTEGER NOT NULL,
                human_resources_used JSONB DEFAULT '[]',
                materials_used JSONB DEFAULT '[]',
                description TEXT DEFAULT '',
                logged_by VARCHAR(255) DEFAULT '',
                created_at TIMESTAMPTZ DEFAULT NOW()
            )
        """))
        await conn.execute(text("CREATE INDEX IF NOT EXISTS ix_task_progress_logs_task ON task_progress_logs (task_id)"))
        await conn.execute(text("CREATE INDEX IF NOT EXISTS ix_task_progress_logs_created ON task_progress_logs (created_at)"))
    except Exception as exc:  # noqa: BLE001
        logger.warning("task_progress_logs table sync skipped: %s", exc)