-- +goose Up
CREATE TABLE assets (
    id TEXT PRIMARY KEY NOT NULL
        CHECK (length(id) = 36),
    creator_subject TEXT NOT NULL
        CHECK (length(trim(creator_subject)) > 0),
    purpose TEXT NOT NULL
        CHECK (purpose IN ('TASK_REFERENCE')),
    media_type TEXT NOT NULL
        CHECK (media_type = 'image/jpeg'),
    size_bytes INTEGER NOT NULL
        CHECK (size_bytes > 0),
    sha256 TEXT NOT NULL
        CHECK (
            length(sha256) = 64
            AND sha256 NOT GLOB '*[^0-9a-f]*'
        ),
    storage_key TEXT NOT NULL UNIQUE
        CHECK (
            length(storage_key) > 0
            AND substr(storage_key, 1, 1) <> '/'
            AND instr(storage_key, '\') = 0
            AND instr(storage_key, '..') = 0
        ),
    created_at TEXT NOT NULL
);

CREATE INDEX assets_creator_created_idx
    ON assets (creator_subject, created_at DESC, id DESC);

CREATE TABLE purchase_tasks (
    id TEXT PRIMARY KEY NOT NULL
        CHECK (length(id) = 36),
    creator_subject TEXT NOT NULL
        CHECK (length(trim(creator_subject)) > 0),
    source_ref TEXT
        CHECK (
            source_ref IS NULL
            OR (
                length(trim(source_ref)) > 0
                AND length(CAST(source_ref AS BLOB)) <= 256
            )
        ),
    title TEXT NOT NULL
        CHECK (
            length(trim(title)) > 0
            AND length(title) <= 120
            AND length(CAST(title AS BLOB)) <= 2048
        ),
    description TEXT NOT NULL
        CHECK (length(CAST(description AS BLOB)) <= 8192),
    sku TEXT NOT NULL
        CHECK (
            length(trim(sku)) > 0
            AND length(CAST(sku AS BLOB)) <= 512
        ),
    image_asset_id TEXT NOT NULL UNIQUE
        REFERENCES assets(id) ON UPDATE RESTRICT ON DELETE RESTRICT,
    quantity INTEGER NOT NULL
        CHECK (quantity > 0),
    max_budget_cents INTEGER
        CHECK (max_budget_cents IS NULL OR max_budget_cents > 0),
    currency TEXT NOT NULL DEFAULT 'CNY'
        CHECK (currency = 'CNY'),
    status TEXT NOT NULL
        CHECK (
            status IN (
                'PENDING',
                'CLAIMED',
                'RUNNING',
                'WAITING_CONFIRMATION',
                'SUCCEEDED',
                'FAILED',
                'CANCELED'
            )
        ),
    version INTEGER NOT NULL
        CHECK (version > 0),
    cancel_reason TEXT
        CHECK (
            cancel_reason IS NULL
            OR length(CAST(cancel_reason AS BLOB)) <= 500
        ),
    canceled_at TEXT,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
);

CREATE UNIQUE INDEX purchase_tasks_creator_source_ref_idx
    ON purchase_tasks (creator_subject, source_ref)
    WHERE source_ref IS NOT NULL;

CREATE INDEX purchase_tasks_creator_created_idx
    ON purchase_tasks (creator_subject, created_at DESC, id DESC);

CREATE INDEX purchase_tasks_creator_status_created_idx
    ON purchase_tasks (
        creator_subject,
        status,
        created_at DESC,
        id DESC
    );

CREATE TABLE task_events (
    id TEXT PRIMARY KEY NOT NULL
        CHECK (length(id) = 36),
    task_id TEXT NOT NULL
        REFERENCES purchase_tasks(id) ON UPDATE RESTRICT ON DELETE CASCADE,
    event_type TEXT NOT NULL
        CHECK (event_type IN ('TASK_CREATED', 'TASK_CANCELED')),
    message TEXT NOT NULL,
    occurred_at TEXT NOT NULL
);

CREATE INDEX task_events_task_occurred_idx
    ON task_events (task_id, occurred_at ASC, id ASC);

CREATE TABLE idempotency_records (
    creator_subject TEXT NOT NULL,
    operation TEXT NOT NULL,
    idempotency_key TEXT NOT NULL,
    request_sha256 TEXT NOT NULL
        CHECK (
            length(request_sha256) = 64
            AND request_sha256 NOT GLOB '*[^0-9a-f]*'
        ),
    resource_type TEXT NOT NULL
        CHECK (resource_type IN ('ASSET', 'PURCHASE_TASK')),
    resource_id TEXT NOT NULL
        CHECK (length(resource_id) = 36),
    created_at TEXT NOT NULL,
    PRIMARY KEY (creator_subject, operation, idempotency_key)
);

-- +goose Down
DROP TABLE IF EXISTS idempotency_records;
DROP INDEX IF EXISTS task_events_task_occurred_idx;
DROP TABLE IF EXISTS task_events;
DROP INDEX IF EXISTS purchase_tasks_creator_status_created_idx;
DROP INDEX IF EXISTS purchase_tasks_creator_created_idx;
DROP INDEX IF EXISTS purchase_tasks_creator_source_ref_idx;
DROP TABLE IF EXISTS purchase_tasks;
DROP INDEX IF EXISTS assets_creator_created_idx;
DROP TABLE IF EXISTS assets;