/*
 This Gradle script provides a markdown changelog based on the commit messages since the last
 build. The resulting changelog is in the markdown format. This supports Jenkins and Travis.
 
 Note: This script is originally from the Inventory Tweaks mod under the MIT license!
 https://github.com/Inventory-Tweaks/inventory-tweaks/blob/develop/build.gradle
 
 Requirements!
 - Git must be installed, and the the executor must have the required git perms. 
*/

def getGitChangelog() {
    try {
        def stdout = new ByteArrayOutputStream()
        def gitHash = System.getenv('GIT_COMMIT')
        def gitPrevHash = System.getenv('GIT_PREVIOUS_COMMIT')
        def travisRange = System.getenv('TRAVIS_COMMIT_RANGE')
        if(gitHash && gitPrevHash) {
            exec {
                commandLine 'git', 'log', '--pretty=tformat:- %s - %aN', '' + gitPrevHash + '...' + gitHash
                standardOutput = stdout
            }
            return stdout.toString().trim()
        } 
        
        else if (gitHash) {
            exec {
                commandLine 'git', 'log', '--pretty=tformat:- %s - %aN', '-1', '' + gitHash
                standardOutput = stdout
            }
            return stdout.toString().trim()
        }
        else if(travisRange) {
            exec {
                commandLine 'git', 'log', '--pretty=tformat:- %s - %aN', '' + travisRange
                standardOutput = stdout
            }
            return stdout.toString().trim()
        } else {
            return "";
        }
    } catch(ignored) {
        return "";
    }
}

ext {

    getGitChangelog = this.&getGitChangelog
}