package chain

import (
	"database/sql"
	"log"

	"github.com/tcs-iptv/tcs/internal/model"
)

// PersistentChain 在 MemoryChain 之上叠加 PostgreSQL 持久化（最小改动模式）。
//
// 设计要点（面向未来平滑替换真实链）：
//   - 业务规则（权限、1:1 强绑定、防换壳重发、状态机）全部复用 MemoryChain，单一真相来源；
//   - 读路径直接走内存（快）；写路径在内存变更成功后「写穿」到 PG 镜像表；
//   - 启动时从 PG「水合」恢复内存状态，进程重启不丢数据；
//   - 链上为权威数据源的设计不变：PG 仅作镜像，写穿失败仅记日志、不阻断主流程。
//
// 未来接入真实 ChainMaker 时，整体以新的 chain.Client 实现替换即可，业务层零改动。
type PersistentChain struct {
	*MemoryChain
	db *sql.DB
}

var _ Client = (*PersistentChain)(nil)

// NewPersistentChain 创建持久化链客户端，并从 PG 水合既有数据。
func NewPersistentChain(db *sql.DB) (*PersistentChain, error) {
	p := &PersistentChain{MemoryChain: NewMemoryChain(), db: db}
	if err := p.hydrate(); err != nil {
		return nil, err
	}
	return p, nil
}

// ---- 写穿（在内存变更成功后镜像到 PG）----

// IssueMA 发码签发：内存绑定成功后镜像内容主记录与全部哈希绑定。
func (p *PersistentChain) IssueMA(role Role, req IssueRequest) (string, error) {
	tx, err := p.MemoryChain.IssueMA(role, req)
	if err != nil {
		return tx, err
	}
	c, _ := p.MemoryChain.QueryContent(req.MACode)
	p.persistContent(c)
	for _, b := range p.snapshotBindings(req.MACode) {
		p.persistBinding(b)
	}
	p.persistTx(req.ContentTwinID, tx, "issueMA")
	return tx, nil
}

// RegisterHashBinding 追加哈希绑定（如转码版）：镜像该条绑定。
func (p *PersistentChain) RegisterHashBinding(role Role, b model.HashBinding) (string, error) {
	tx, err := p.MemoryChain.RegisterHashBinding(role, b)
	if err != nil {
		return tx, err
	}
	p.persistBinding(b)
	p.persistTx(b.ContentTwinID, tx, "registerHashBinding")
	return tx, nil
}

// RegisterMapping 注册三方映射：镜像该映射（按唯一键幂等）。
func (p *PersistentChain) RegisterMapping(role Role, mp model.Mapping) (string, error) {
	tx, err := p.MemoryChain.RegisterMapping(role, mp)
	if err != nil {
		return tx, err
	}
	p.persistMapping(mp)
	p.persistTx(mp.ContentTwinID, tx, "registerMapping")
	return tx, nil
}

// RecordVersionChange 版本变更：镜像到 version_history。
func (p *PersistentChain) RecordVersionChange(vc model.VersionChange) (string, error) {
	tx, err := p.MemoryChain.RecordVersionChange(vc)
	if err != nil {
		return tx, err
	}
	p.exec(`INSERT INTO version_history
		(content_twin_id, version, change_reason, prev_hash, new_hash, reaudit_required, reaudit_status, affected_episode)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8)`,
		vc.ContentTwinID, vc.Version, vc.ChangeReason, vc.PrevHash, vc.NewHash,
		vc.ReauditRequired, vc.ReauditStatus, vc.AffectedEpisode)
	return tx, nil
}

// Revoke 整剧下架：镜像内容状态。
func (p *PersistentChain) Revoke(role Role, maCode, reason string) (MappingsResult, error) {
	res, err := p.MemoryChain.Revoke(role, maCode, reason)
	if err != nil {
		return res, err
	}
	p.updateStatus(maCode, model.StatusRevoked)
	return res, nil
}

// Restore 整剧恢复上架：镜像内容状态。
func (p *PersistentChain) Restore(role Role, maCode string) error {
	if err := p.MemoryChain.Restore(role, maCode); err != nil {
		return err
	}
	p.updateStatus(maCode, model.StatusPublished)
	return nil
}

// RevokeEpisode 集级下架：镜像该集 revoked 标记。
func (p *PersistentChain) RevokeEpisode(role Role, maCode string, episode int, reason string) error {
	if err := p.MemoryChain.RevokeEpisode(role, maCode, episode, reason); err != nil {
		return err
	}
	p.updateEpisodeRevoked(maCode, episode, true, reason)
	return nil
}

// RestoreEpisode 集级恢复：镜像该集 revoked 标记。
func (p *PersistentChain) RestoreEpisode(role Role, maCode string, episode int) error {
	if err := p.MemoryChain.RestoreEpisode(role, maCode, episode); err != nil {
		return err
	}
	p.updateEpisodeRevoked(maCode, episode, false, "")
	return nil
}

// SetContentStatus 状态流转（入库/发布等）：镜像内容状态。
func (p *PersistentChain) SetContentStatus(maCode, status string) error {
	if err := p.MemoryChain.SetContentStatus(maCode, status); err != nil {
		return err
	}
	p.updateStatus(maCode, status)
	return nil
}

// ---- PG 写入小工具（best-effort，失败仅记日志）----

func (p *PersistentChain) exec(q string, args ...any) {
	if _, err := p.db.Exec(q, args...); err != nil {
		log.Printf("chain/pg: 写穿失败(忽略，镜像为非权威): %v", err)
	}
}

func (p *PersistentChain) persistContent(c model.Content) {
	var issueDate any
	if c.IssueDate != "" {
		issueDate = c.IssueDate
	}
	p.exec(`INSERT INTO content_registry
		(content_twin_id, ma_code, ma_type, title, episode_count, status, issuer, issue_date, created_at)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9)
		ON CONFLICT (content_twin_id) DO UPDATE SET status=EXCLUDED.status, updated_at=NOW()`,
		c.ContentTwinID, c.MACode, c.MAType, c.Title, c.EpisodeCount, c.Status, c.Issuer, issueDate, c.CreatedAt)
}

func (p *PersistentChain) persistBinding(b model.HashBinding) {
	p.exec(`INSERT INTO hash_binding
		(content_twin_id, hash_type, hash_value, merkle_root, file_format, resolution, duration, version, parent_hash, episode, revoked, revoked_reason, created_by)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13)`,
		b.ContentTwinID, string(b.HashType), b.HashValue, b.MerkleRoot, b.FileFormat, b.Resolution,
		b.Duration, b.Version, b.ParentHash, b.Episode, b.Revoked, b.RevokedReason, b.CreatedBy)
}

func (p *PersistentChain) persistMapping(mp model.Mapping) {
	p.exec(`INSERT INTO identity_mapping
		(content_twin_id, party, party_id, party_name, cdn_endpoint)
		VALUES ($1,$2,$3,$4,$5)
		ON CONFLICT (content_twin_id, party, party_id) DO UPDATE SET cdn_endpoint=EXCLUDED.cdn_endpoint`,
		mp.ContentTwinID, string(mp.Party), mp.PartyID, mp.PartyName, mp.CDNEndpoint)
}

func (p *PersistentChain) persistTx(ctid, txID, method string) {
	p.exec(`INSERT INTO chain_tx (content_twin_id, tx_id, method, status)
		VALUES ($1,$2,$3,'confirmed') ON CONFLICT (tx_id) DO NOTHING`,
		ctid, txID, method)
}

func (p *PersistentChain) updateStatus(maCode, status string) {
	p.exec(`UPDATE content_registry SET status=$1, updated_at=NOW() WHERE ma_code=$2`, status, maCode)
}

func (p *PersistentChain) updateEpisodeRevoked(maCode string, episode int, revoked bool, reason string) {
	p.exec(`UPDATE hash_binding hb SET revoked=$1, revoked_reason=$2
		FROM content_registry cr
		WHERE hb.content_twin_id = cr.content_twin_id AND cr.ma_code=$3 AND hb.episode=$4`,
		revoked, reason, maCode, episode)
}

// snapshotBindings 复制某 MA 码当前的内存绑定（同包访问，读锁保护）。
func (p *PersistentChain) snapshotBindings(maCode string) []model.HashBinding {
	p.mu.RLock()
	defer p.mu.RUnlock()
	src := p.bindings[maCode]
	out := make([]model.HashBinding, len(src))
	copy(out, src)
	return out
}

// ---- 启动水合：从 PG 镜像恢复内存状态 ----

func (p *PersistentChain) hydrate() error {
	// 1) 内容主表 + 建立 ctid -> maCode 映射
	ctidToMA := map[string]string{}
	rows, err := p.db.Query(`SELECT content_twin_id, ma_code, COALESCE(ma_type,''), title,
		COALESCE(episode_count,1), status, COALESCE(issuer,''),
		COALESCE(to_char(issue_date,'YYYY-MM-DD'),''), created_at FROM content_registry`)
	if err != nil {
		return err
	}
	n := 0
	for rows.Next() {
		var c model.Content
		if err := rows.Scan(&c.ContentTwinID, &c.MACode, &c.MAType, &c.Title,
			&c.EpisodeCount, &c.Status, &c.Issuer, &c.IssueDate, &c.CreatedAt); err != nil {
			rows.Close()
			return err
		}
		p.contents[c.MACode] = c
		ctidToMA[c.ContentTwinID] = c.MACode
		n++
	}
	rows.Close()

	// 2) 哈希绑定（含集级、转码、感知）+ 重建防换壳哈希索引
	bRows, err := p.db.Query(`SELECT content_twin_id, hash_type, hash_value, COALESCE(merkle_root,''),
		COALESCE(file_format,''), COALESCE(resolution,''), COALESCE(duration,0), version,
		COALESCE(parent_hash,''), episode, revoked, COALESCE(revoked_reason,''), COALESCE(created_by,'')
		FROM hash_binding ORDER BY id`)
	if err != nil {
		return err
	}
	for bRows.Next() {
		var b model.HashBinding
		var ht string
		if err := bRows.Scan(&b.ContentTwinID, &ht, &b.HashValue, &b.MerkleRoot, &b.FileFormat,
			&b.Resolution, &b.Duration, &b.Version, &b.ParentHash, &b.Episode, &b.Revoked,
			&b.RevokedReason, &b.CreatedBy); err != nil {
			bRows.Close()
			return err
		}
		b.HashType = model.HashType(ht)
		ma := ctidToMA[b.ContentTwinID]
		if ma == "" {
			continue
		}
		p.bindings[ma] = append(p.bindings[ma], b)
		if (b.HashType == model.HashFile || b.HashType == model.HashTranscoded) && b.HashValue != "" {
			if _, ok := p.hashIndex[b.HashValue]; !ok {
				p.hashIndex[b.HashValue] = ma
			}
		}
	}
	bRows.Close()

	// 3) 三方映射
	mRows, err := p.db.Query(`SELECT content_twin_id, party, party_id, COALESCE(party_name,''), COALESCE(cdn_endpoint,'')
		FROM identity_mapping ORDER BY id`)
	if err != nil {
		return err
	}
	for mRows.Next() {
		var mp model.Mapping
		var party string
		if err := mRows.Scan(&mp.ContentTwinID, &party, &mp.PartyID, &mp.PartyName, &mp.CDNEndpoint); err != nil {
			mRows.Close()
			return err
		}
		mp.Party = model.Party(party)
		if ma := ctidToMA[mp.ContentTwinID]; ma != "" {
			p.mappings[ma] = append(p.mappings[ma], mp)
		}
	}
	mRows.Close()

	// 4) 版本变更
	vRows, err := p.db.Query(`SELECT content_twin_id, version, COALESCE(change_reason,''), COALESCE(prev_hash,''),
		COALESCE(new_hash,''), reaudit_required, COALESCE(reaudit_status,''), COALESCE(affected_episode,0)
		FROM version_history ORDER BY id`)
	if err != nil {
		return err
	}
	for vRows.Next() {
		var vc model.VersionChange
		if err := vRows.Scan(&vc.ContentTwinID, &vc.Version, &vc.ChangeReason, &vc.PrevHash,
			&vc.NewHash, &vc.ReauditRequired, &vc.ReauditStatus, &vc.AffectedEpisode); err != nil {
			vRows.Close()
			return err
		}
		if ma := ctidToMA[vc.ContentTwinID]; ma != "" {
			p.versions[ma] = append(p.versions[ma], vc)
		}
	}
	vRows.Close()

	if n > 0 {
		log.Printf("chain/pg: 已从 PostgreSQL 水合 %d 条内容记录", n)
	}
	return nil
}