src/main/kotlin/de/uapcore/lightpit/servlet/FeedServlet.kt

/*
 * Copyright 2021 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package de.uapcore.lightpit.servlet

import de.uapcore.lightpit.AbstractServlet
import de.uapcore.lightpit.HttpRequest
import de.uapcore.lightpit.dao.DataAccessObject
import de.uapcore.lightpit.entities.IssueHistoryData
import de.uapcore.lightpit.entities.IssueHistoryEntry
import de.uapcore.lightpit.viewmodel.IssueDiff
import de.uapcore.lightpit.viewmodel.IssueFeed
import de.uapcore.lightpit.viewmodel.IssueFeedEntry
import java.text.SimpleDateFormat
import javax.servlet.annotation.WebServlet

@WebServlet(urlPatterns = ["/feed/*"])
class FeedServlet : AbstractServlet() {

    init {
        get("/%project/issues.rss", this::issues)
    }

    private fun String.convertLF() = replace("\r", "").replace("\n", "<br>")

    private fun fullContent(issue: IssueHistoryData) = IssueDiff(
        issue.id,
        issue.subject,
        issue.component,
        issue.status.name,
        issue.category.name,
        issue.subject,
        issue.description.convertLF(),
        issue.assignee,
        issue.eta?.let { SimpleDateFormat("dd.MM.yyyy").format(it) } ?: "",
        issue.affected,
        issue.resolved
    )

    private fun diffContent(cur: IssueHistoryData, next: IssueHistoryData): IssueDiff {
        val prev = fullContent(next)
        val diff = fullContent(cur)
        // TODO: compute and apply diff
        return diff
    }

    /**
     * Generates the feed entries.
     * Assumes that [historyEntry] is already sorted by timestamp (descending).
     */
    private fun generateFeedEntries(historyEntry: List<IssueHistoryEntry>) =
        if (historyEntry.isEmpty()) emptyList()
        else historyEntry.zipWithNext().map { (cur, next) ->
            IssueFeedEntry(
                cur.time, cur.type, diffContent(cur.data, next.data)
            )
        }.plus(
            historyEntry.last().let { IssueFeedEntry(it.time, it.type, fullContent(it.data)) }
        )

    private fun issues(http: HttpRequest, dao: DataAccessObject) {
        val project = http.pathParams["project"]?.let { dao.findProjectByNode(it) }
        if (project == null) {
            http.response.sendError(404)
            return
        }

        val days = http.param("days")?.toIntOrNull() ?: 30

        val issueHistory = dao.listIssueHistory(project.id, days)
        // TODO: add comment history depending on parameter

        http.view = IssueFeed(project, generateFeedEntries(issueHistory))
        http.renderFeed("issues-feed")
    }
}