package jmap

import (
	"encoding/json"
	"strconv"

	"mailgoserver/internal/db"
)

// jmapIdentity is RFC 8621 §6.1's Identity object.
type jmapIdentity struct {
	ID            string `json:"id"`
	Name          string `json:"name"`
	Email         string `json:"email"`
	TextSignature string `json:"textSignature"`
	HTMLSignature string `json:"htmlSignature"`
	MayDelete     bool   `json:"mayDelete"`
}

const primaryIdentityID = "primary"

// identityRow pairs an Identity id with the address it represents — "primary" for the
// mailbox's own address, "alias-<aliasID>" for each active send-as alias
// (esrv_mailbox_aliases.can_send_as) — see identityGet's doc comment for why
// aliases (not S/MIME/PGP identities) are the source here.
type identityRow struct {
	id, email string
}

func identityRows(b *Backend, mbox *db.Mailbox) ([]identityRow, error) {
	out := []identityRow{{id: primaryIdentityID, email: mbox.Email}}
	aliases, err := b.DB.ListAliasesForMailbox(mbox.ID)
	if err != nil {
		return nil, err
	}
	for _, a := range aliases {
		if a.IsActive && a.CanSendAs {
			out = append(out, identityRow{id: "alias-" + strconv.FormatInt(a.ID, 10), email: a.Email})
		}
	}
	return out, nil
}

func buildIdentity(b *Backend, mbox *db.Mailbox, row identityRow) jmapIdentity {
	id := jmapIdentity{ID: row.id, Name: mbox.Email, Email: row.email, MayDelete: false}
	sig, err := b.DB.GetDefaultSignature(mbox.ID, false, row.email)
	if err == nil && sig != nil {
		id.HTMLSignature = sig.ContentHTML
	}
	return id
}

type identityGetArgs struct {
	IDs *[]string `json:"ids"`
}

type identityGetResult struct {
	AccountID string         `json:"accountId"`
	State     string         `json:"state"`
	List      []jmapIdentity `json:"list"`
	NotFound  []string       `json:"notFound"`
}

// identityGet is Identity/get (RFC 8621 §6.2). Identities are synthesized from this
// mailbox's own address plus its active send-as aliases (esrv_mailbox_aliases) — not
// from the S/MIME/PGP identity tables, which are signing/encryption key material, a
// different concept from JMAP's "an address + display name + signature you can send
// from" Identity object. State is just the mailbox's own aliases/signatures being
// static within a session in practice; a fixed "1" is sufficient since neither
// changes via any method this server implements.
func identityGet(b *Backend, mbox *db.Mailbox, rawArgs json.RawMessage) (any, *methodError) {
	var args identityGetArgs
	if err := json.Unmarshal(rawArgs, &args); err != nil {
		return nil, &methodError{Type: "invalidArguments", Description: err.Error()}
	}
	rows, err := identityRows(b, mbox)
	if err != nil {
		return nil, &methodError{Type: "serverFail", Description: err.Error()}
	}
	result := identityGetResult{AccountID: strconv.FormatInt(mbox.ID, 10), State: "1", List: []jmapIdentity{}, NotFound: []string{}}
	if args.IDs == nil {
		for _, row := range rows {
			result.List = append(result.List, buildIdentity(b, mbox, row))
		}
		return result, nil
	}
	byID := make(map[string]identityRow, len(rows))
	for _, row := range rows {
		byID[row.id] = row
	}
	for _, id := range *args.IDs {
		row, ok := byID[id]
		if !ok {
			result.NotFound = append(result.NotFound, id)
			continue
		}
		result.List = append(result.List, buildIdentity(b, mbox, row))
	}
	return result, nil
}

type identitySetArgs struct {
	Update map[string]json.RawMessage `json:"update"`
}

type identitySetResult struct {
	AccountID  string                  `json:"accountId"`
	OldState   string                  `json:"oldState"`
	NewState   string                  `json:"newState"`
	Updated    map[string]any          `json:"updated"`
	NotCreated map[string]*methodError `json:"notCreated"`
	NotUpdated map[string]*methodError `json:"notUpdated"`
}

// identitySet is Identity/set (RFC 8621 §6.3) — limited to updating htmlSignature on
// an existing identity (routed to db.SetDefaultSignature/db.SetSignatureAliasDefault,
// creating a signature row via db.CreateSignature if none exists yet). No create/
// destroy: the underlying send-as grant stays admin-controlled via
// esrv_mailbox_aliases.can_send_as, unchanged by this method — an Identity here isn't
// an independent object, it's a view onto that grant plus a signature.
func identitySet(b *Backend, mbox *db.Mailbox, rawArgs json.RawMessage) (any, *methodError) {
	var args identitySetArgs
	if err := json.Unmarshal(rawArgs, &args); err != nil {
		return nil, &methodError{Type: "invalidArguments", Description: err.Error()}
	}
	rows, err := identityRows(b, mbox)
	if err != nil {
		return nil, &methodError{Type: "serverFail", Description: err.Error()}
	}
	byID := make(map[string]identityRow, len(rows))
	for _, row := range rows {
		byID[row.id] = row
	}

	result := identitySetResult{
		AccountID: strconv.FormatInt(mbox.ID, 10), OldState: "1", NewState: "1",
		Updated: map[string]any{}, NotCreated: map[string]*methodError{}, NotUpdated: map[string]*methodError{},
	}
	for idStr, rawPatch := range args.Update {
		row, ok := byID[idStr]
		if !ok {
			result.NotUpdated[idStr] = &methodError{Type: "notFound"}
			continue
		}
		var patch map[string]json.RawMessage
		if err := json.Unmarshal(rawPatch, &patch); err != nil {
			result.NotUpdated[idStr] = &methodError{Type: "invalidPatch", Description: err.Error()}
			continue
		}
		htmlRaw, ok := patch["htmlSignature"]
		if !ok {
			if len(patch) == 0 {
				result.Updated[idStr] = nil
				continue
			}
			result.NotUpdated[idStr] = &methodError{Type: "invalidProperties", Description: "only htmlSignature updates are supported"}
			continue
		}
		var html string
		if err := json.Unmarshal(htmlRaw, &html); err != nil {
			result.NotUpdated[idStr] = &methodError{Type: "invalidPatch", Description: err.Error()}
			continue
		}
		if err := setIdentitySignature(b, mbox, row, html); err != nil {
			result.NotUpdated[idStr] = &methodError{Type: "serverFail", Description: err.Error()}
			continue
		}
		result.Updated[idStr] = nil
	}
	return result, nil
}

func setIdentitySignature(b *Backend, mbox *db.Mailbox, row identityRow, html string) error {
	sig, err := b.DB.GetDefaultSignature(mbox.ID, false, row.email)
	if err != nil {
		return err
	}
	if sig != nil {
		return b.DB.UpdateSignature(mbox.ID, sig.ID, sig.Name, html)
	}
	name := "JMAP signature (" + row.email + ")"
	newID, err := b.DB.CreateSignature(mbox.ID, name, html)
	if err != nil {
		return err
	}
	if row.id == primaryIdentityID {
		return b.DB.SetDefaultSignature(mbox.ID, newID, false)
	}
	return b.DB.SetSignatureAliasDefault(mbox.ID, newID, row.email, false)
}